Mold for manufacture of brake drums



Nov. 29, 1938. D. J. CAMPBELL ET AL 2,138,624

v MOLD FOR MANUFACTURE oF BRAKE DRUMS Filed April 26, 1957 v 4 Sheets-Sheet l By rimas; na/(E.

A TToR/vE-y [NVN-TOR Nov. 29, 1938.

D. J, CAMPBELL ET AL MOLD FOR lvxiz'xNUFACTURE oF BRAKE DRUMS 4 Sheets-Sheet 2 Filed Aprilge, 1937 Nov. 29, w38.4 D. J. CAMPBELL ET AL. '72,138,624

MOLD FOR MANUFAGTURE OF BRAKE DRUMS 4 Sheet s-Sheet 3 /N VEA/TOR .Do/VAL J. (bMPELL BY 6i/afgis W .0H/cr A TTORNEY ?atented ov. 29, 1938 UNITE n ATENT- oFFlcI-.z

Mom rca MANUFAE or DRUM nomad r. phen, sp1-ingaan Township, ot-

tawa County, and Charles W. Dake, Grand Haven, Mich., assignors to Campbell, Wyant & Cannon Foundry Company, Muskegon This invention relates to improvements in molds for brake drum manufacture, and particularly to a mold for producing brake drums of composite wrought steel and cast iron brake drums such as are used on motor vehicles.

s The brake drum which is to be produced includes a wrought metal brake drum shell or band which is lined with a lining of cast metal molecularly bonded therewith to provide in effect an integral brake d structure through which heat generated inthe 4drum during the operation of the brake mechanism, when the braking shoes frictionally engage thereagalnst, passes uniformly through the drum where itis readily disl 'sipated by the surrounding atmosphere. The

brake drum when completed includes a supporting back or web also of wrought metal which may be either integral with the wrought metal shell described or separately attached as by spot welding, riveting or other suitable connecting means. c

' In our invention a novel mold and apparatus is provided for eiiectively casting molten metal into engagement with the inner side of the wrought metal vshell in such a manner as to secure an intermolecular joinder of the cast metal with the wrought metal shell, thereby providing a lining of cast metal secured to the shell or band which serves as a support Afor the cast metal and gives resistance against breakage while theV cast metal provides a superior braking surface. The invention includes many novel details of structure in the mold for practically and effectively attaining the intermolecular Joinder of the A cast metal with the supporting shell or ring therefor and without chilling. the molten metal or warping' and vvdistorting the shell. 'Ihe teni perature of the molten metal as poured into the mold is very high and above the melting point o of the supporting shell metal in order to attain the intermolecular joinder of the two. In commercial practice the brake drum shell is of sheet" 55 neously cast.

Fig. 2 is a plan view of the moldfshown in Fig. 1.

Figs.` 3'and 4 are horizontal sections substantially on the planes of lines 3-3 and 4-4 of Fig. 1.

Fig. 5 is a vertical section, somewhat similar to that shown in Fig. 1, except the casting of the liner to but one brake drum shell of a formed steel shell is secured, and shows .the method as employed in producing one drum only. 10

Fig, 6 is an elevation and partial section of a completed drum shell or band.

Fig." 7 is a perspective view of one form -of reinforcing ring which is located around the sheet metal shell for Vsupporting the shell against en- 15 largement, the'inner side of which the molten 'casting metal is deposited against, and f-f'r" Referring to Fig. 1, a mold made of a plu- 25 rality of superimposed sections or portions is provided. The lower mold section l is contained in a surrounding flask 2 and rests upon a base 3.

A plurality of duplicate moldsections 4, as many as may be conveniently used, are placed in super- 30 imposed relation, one over the other, above the lower mold section I, said mold sections 4 being retained within flasks 6. Above the uppermost mold section 4 is a cope section 6 within ask 1. The adjacent upper and lower edge portions 012,35 the several flasks 2, 4 and 8 have outwardly ex-` tending flanges over which, at proper spaced apart points, clamps 8 are located to hold the sections together.

Each ofo the mold sections 4 has a central 40 cavity, open at'its under side, within which is located the wrought metal brake drum shell or band 9,v which is of ,substantially cylindrical form and at its upper edges as located in the mold, has an inturned horizontal annular iiange I0. The lower edge portion of the shell 9 is shaped preferably with an outwardly extending comparatively wide annular rib il, the lower edge of which terminates substantially flush with the lower side of the mold section 4. -.The mold Sec-v tions 4, as well as the sections I and 6, are made yfrom suitable molding sand deposited in the a'sks in accordance with usual molding practice around Y a suitable pattern and also aroundy the sheet metal sneu 9 and the` aange lo thereof and also 55 the shell 9 and ring I2.

over the auxiliary heat conserving and shell reinforcing rings I or I5 and I5a which are now about to be described.

Around the brake drum -ring 9 a cylindrical channular ring I2 of sheet metal is located in spaced relation, at its upper edges having an inturned preferably continuous. annular iiangev I3 which extends over the ilange IIJ. This provides a continuous annular air space I4 between A strengthening and reinforcing ring` I5 of a shallow channel shape nel ring I5 is split at `one side as shown in Fig. '7.

A core I6 is located within the recess of each mold section 4 which is surrounded by the brake drum shell 9, there being defined between. its periphery and the inner side of the shell 9 a mold cavity I1. The cores I6 have alined vertical sprues I8, the upper ends of which join with the sprue openings I9 at the upper part of each of the mold sections 4, as shown. Associated with each mold section 4, are radial gates 20 extending outwardly, joining with the said sprue openings I9, and at their outer ends connected to circular groove 2I wfrom which a large number of spaced apart gates 22 extend outward and connect with the lower end of the mold cavity I1. 'Ihe gates at 22 are spaced apart by interposed spacing projections 23, preferably frpm the mold section 4, and, as shown in Fig. 4, the gates at 22.

widen laterally and decrease in vertical dimension from their inner ends outwardly. This provides for a substantially uniform rate of iiow velocity from the gates into the mold cavity I1 and continuously around the lower end of the whole of cavity I1 when theA molten metal is poured into the mold. The upper pouring section 6 which does not have any mold cavity I1 to be illed with molten iron is therefore shaped at its lower side to ll .the radial gates 20 and groove 2I at the upper side of the next adjacent lower section 4.

At the upper Aside of each of the cores I6 are one or more recesses 24 (see Fig. 3) which provide overilow reservoirs for the surplus melted iron flowed through the mold cavity in contact with the inner periphery of the drum shell to heat the surface thereof to a temperature that will permit the cast metal lining to become molecularly joined with the drum shell and when it has reached the uppermost points in the cavity I 1.

As shown, the upper or cope section 6 has a central pouring opening 25 at the lower part' of which is a skim gate 26 resting upon the upper side of the next lowermost section 4. The metal, when poured into the opening at 25, passes through the gate 26 and first fills the gates and the mold cavity connected therewith in the lowermost of the sections, thereby lining the shell 9 and its rib II with the cast metal. The gates are filled with metal :ill` and the sprues with the metal at 29, while the overilow pockets at 24. are filled with the metal indicated at 28 in Fig. 1. The pouring of the molten metal is continuedA until it has reached above the skim gate 26.

With this construction of mold the sheet metal shells 9 are spaced from the sand of the mold sections 4 by the rings I2 and I5, thereby providing insulating air spaces I4 which prevents quick dissipation of heat and chillingl of the molten metal when it impinges and engages the inner sides of the rings 9. The channel rings I5 in Said annular air spaces hold the rings 9 against outward deformation which otherwise would occur on` account of the softening and lessening of resistance of the rings 9 when the very high temperature molten metal comes thereagainst. When molten iron is used as the metal to be cast to make the lining I1 and comes against `a steel brake drum shell 9 the temperature of the molten iron preferably will be considerably above that normally used in regular foundry practice. The tem, perature of molten iron as taken from cupolas in foundry practice is usually near 2500 F., but it may reach 2600 F. Therefore, heating such` molten iron as it is taken from the foundry cupola in an electric or other furnace to raise the temperature for example to a higher temperature such as 2850 F. or at times to 3000 F. is desirable and is preferred for the attainment of successful molecular fusion of the cast iron to the steel shell 9, which fusion must be such. that there is a complete intermolecular joinder of the cast iron and steel over their entire opposed areas where they come into contact engagement with each other. The annular rib II in the shell 9 is to provide an increased body of cast iron at the open sideof the brake drum so as to resist rupture and withstand stresses which the brake drum has to withstand.

In Fig. 5 a steel brakedrum shell is shown having the steel shell 9 and a continuous supporting web or back |00 which is merely a continuation of a flange I0 as shown in Fig. 1. When a shell 9 having an inturned iiangeV I0 is lined with the cast metal at 21 so as to provide a composite steel and cast iron member, such las shown in Fig. 6, the

drum is completed by permanently connecting a is providedwith outwardly extending heat dissii. I pating corrugations 3| which are filled when the cast iron liner 2'I is cast as molten metal thereagainst. In such case lthe strengthening and reinforcing ring I5a is split transversely and correspondingly corrugated, as at 32 in the band portion thereof to t over the ribs 3l.

With this mold and with the method of casting described composite brake drums of steel and cast iron wherein the steel is used as an outer supporting shell for a cast iron braking band within and molecularly bonded to the steel shell isreadily produced in a practical manner.

A divisional application covering only the method above described has been filed and bears filing date as of May 9, 1938, and Serial No. 206,756.

The invention is dened in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope. I

We claim:

1. For-use in brake drum manufacture, a flask having a sand mold therein, said mold having a cavity extending upwardly at its underside. a core within said cavity of less cross sectional area than the cavity of the mold thereby providinganannular recess between sald mold and core, said core having a sprue hole extending therethrough with gates at the lower side thereof leading to the said recess extended around the core, a sheet metal brake drum shell around the core and spaced therefrom and also spaced from the sides of said mold cavity, and a metal shield ring construction containing the elements in combination dei-ined in claim 1, combined with a reinforcing ring of sheet metal having a channel cross section, having a web thereof lying against the outer side of said shell and the flanges eX- tending outwardly and bearing against the inner side of said shield ring, as and for the purposes specified.

4. A molding apparatus comprising a drag and a cope, each including a surrounding iiask and a sand mold therein, said cope mold having a substantially cylindrical cavity in its lower side extending toward but short of the upper side thereof, a substantially cylindrical vcore located in said cavity, having its peripheral surfaces spaced from the sides of said cavity, said core and cope having vertical sprue openings and there-being gates between said core and drag mold leading from the lower end Aof the core sprue opening to the recess around the core, a. sheet metal shield of cylindrical form located within said cope mold cavity and against the periphery of the mold, a sheet metal substantially cylindrical shell located within said cavity and spaced from both said shield and core, the upper end of said shell having an inturned horizontal ange extending Vover the outer edgepor'tions of said core.

5. A construction containing the elements in combination dened in 4-claim 4, said core adjacent its outer edges resting upon said'drag mold on the plurality of spaced apart vsupporting posts extending between the cere and drag mold adjacent the outer edges of the core, said gates from the lower end of the sprue opening extending radially outward and said drag mold inits upper side having a continuous circular groove therein connecting the outer ends of the gates and located at the inner sides of said posts, as

specified.

6. A construction containing` the elements in combination as defined in claim 4, said drag mold at its upper side having a continuous circular groove therein at below and adjacent the outer portions of said core, supporting posts in spaced apart relation between the core and drag mold exterior of said groove, providing a plurality of spaced apart gates leading from the groove to the mold recess between the core and said band, said last mentioned gates iprogresr'sively increasing in 'width and decreasing in height outwardly, as

specified.

7. For use in brake drum manufacture, a mold comprising upper and lower mold sections, a plurality of other mold sections interposed therebetween, each of said last named sections having a substantially cylindrical mold cavity with a substantially cylindrical core therein, an annular recess between said core and the inner periphery of said cavity, a sprue hole in said core communicating with an opening in said upper section, an overflow cavity between some of said sections communicating with said annular recess, a circular groove in spaced relation to said recess and sprue hole, a plurality of gates extending from said sprue hole to said groove, "a plurality of gates extending from said groove to said mold recess, a

wrought, metal brake drum shell in said recess, a cylindrical channular ring surrounding the outer periphery of said shell and in part radially spaced therefrom. j

8. The combination of elements as defined in claim 7, said channular ring also engaging said shell in part, and a reinforcing ringv interposed between said shell .and said ring.

DONALD J. CAMPBELL. CHARLES w. DAKE.

:sol 

